Ignition testing and engine treating device



July 13, 1943. H. G. LEHMANN IGNITION TESTING AND ENGINE TREATING DEVICE Filed Nov. 14 1940 2 Sheets-Sheet l N W m r R m m m vim m: A I. my B July 13, 19 3- H. G. LEHMANN IGNITION TESTING AND ENGINE TREATING DEVICE Filed Nov. 14, 1940 2 Sheets-Sheet 2 I ll 1 INVENTOR Z G. Lehman?! ATTORNE a Herb BY Wm KM Patented July 13, 1943' rem-non 'rns'rmo AND ENGINE memo DEVICE Herbert G. Lehmann, Bridgeport, Conm, assignor to Casco Products Corporation, Bridgeport, Conn.. a corporation of Connecticut Application November 14, 1940, Serial No. 365,587 p 16 Claims.

The present invention relates to improvements in a testing device for ignition systems of automobile engines including also means for degumming the cylinders and valves of the engme.

It is an object of the present invention to provide a device for the aforesaid purpose of relatively simple and inexpensive construction which provides an efiicient and convenient means for testing the engine and for degumming the cylinders and valves thereof.

Another object is to provide a device for testing the efficiency of the ignition in each cylinder and of determining the resistance or spacing of the .spark plug points in a relatively accurate manner.

A further object is to provide a device for accomplishing the aforesaid tests wherein the danger of fire from exposed sparks in the neighborhood of combustible fumes is avoided.

Still another object is to provide a device for the aforesaid purpose wherein no high tension contacts are exposed, whereby the danger of shocks to the gperator of the device is avoided.

It it also an object to provide an adjustable 'spark gap mechanism of novel construction, for determining the spacing or resistance. of spark plug points of an engine in a testing device having the advantages set forth in the preceding paragraphs.

A further object is to provide a reservoir for introducing a treatment fluid into the cylinders of an automabile engine, having outlet connections for admitting a degumming fluid through the carburetor, whereby the rate of flow of the liquid is automatically reglated.

Other features and advantages will appear from the following description referring to the accompanying drawings, in which;

Figure 1 is a front elevation of the testing device of the present invention, including a reservoir for a degumming liquid, tube and filter elements of which are shown in cross-section, and including in dotted lines the details of the clips for connecting the leads of the testing device to the spark plugs and ground connection in an automobile engine.

Fig. 2 is a rear elevation of the control panel of the testing device of Fig. 1, the rear wall of the casing of said device being cut away and I of an adjustable spark gap including a sliding contact and a carrier strip therefor, the section being taken along line 4-4 in Fig. 2.

Fig. 5 is a schematic front view of the testing device and liquid reservoir of the present invention, showing the leads thereof connected to the spark plugs and ground connection of an automobile engine, and a tube from the liquid reservoir connected to the carburetor.

Fig. '6 is a detail in perspective showing the disposition of the end of the outlet tube from the liquid reservoir inserted into a venturi of the carbureter intake for the treatment of the cylinders or valves of the engine with degumming liquid contained in the reservoir.

According to the present invention, a testing device is provided having a casing within which is mounted a luminous gaseous discharge tube, with means for connecting the tube successively to a series of contacts which are adapted to be joined by suitable leads to the high tension terminals of the spark plugs of an automobile engine, and a series of adjustable spark gaps, one terminal of each of which is also adapted to be connected to the high tension terminals of the said spark plugs. The opposite terminal of the luminous discharge tube as well as the other terminals of the spark gaps are grounded through the casing of the device by means of a suitable lead adapted to be connected to a portion of the engine block. All external metal parts of the casing are grounded, and all of the high tension connections are either housed within the casing or suitably insulated, whereby the operator is protected from shocks while manipulating the testing device. Furthermore, the disposition of the adjustable spark gaps within the casing protects the sparks formed between the points thereof from access of combustible fumes which are liable to be present in the vicinity of an automobile engine, especially in garages and thus the danger of fire or explosion and the accompanying damage to life and property is avoided.

According to the invention, a single luminous discharge tube is provided for testing each of the spark plugs and is mounted in fixed position witheliminated in testing the various spark plugs of the engine, one at a time.

readilyobserved against a dark background.

Preferably, the windows contain magnifying lenses whereby the observation of the sparks is still more facilitated.

Referring to the drawings, the testing device I! of the present invention is housed in a sheet metal casing l I, closed at the front by a panel II of wood, Bakelite or similar insulating material, which is seated against a shoulder 13 formed near the edge of the metal casing. The panel I! is preferably provided with a facing 14 of smooth dielectric material and the panel and facing are secured to the casing II by meansof a plurality of bolts II threaded into the rear wall of the said casing.

An elongated aperture I8 is formed near the top of the panel and facing, and a luminous electric discharge tube I1 is supported by a pair of metal clips I! and II behind the apertures. The said clips constitute means for connecting the electrodes of the tube to a source of high tension E. M. I". and a ground. The tube I1 is filled with a rarifled gas such as neon which becomes luminous under the influence of the high tension discharge. A window of suitable transparent material, for instance, a transparent plastic resin or glass, covers the aperture 16 and may be supported by means of integral flanges 20a clamped between the panel I! and the facing II as shown.

A series of circular apertures II are also formed in the panel and facing, and each is closed by a convex lens 22 of transparent or translucent material, such as glass or plastic resin, supported in position by means of a peripheral flange 220 which is clamped between the panel and the facing. The apertures and lenses are provided for observing sparks formed in spark gaps behind the panel.

Above each aperture II, a metal clip 28 is fastened to the panel II by means of a bolt 23a. The free end of each clip 2'! projects outwardly from the rear surface of the panel and is soldered to an insulated lead 24 which extends through an insulating bushing wall of the casing H. The outer end of the said lead terminates in a spring clip 28 of suitable construction for'manual attachment to, or removal from, the high tension terminals of the spark plugs of an automobile engine. The clips II may advantageously comprise a pair of separable metal jaws. I'I, urged together by a compression spring II, the manually gripped portions of the clip being surrounded by a flexible cover 20 of insulating material such as soft rubber.

Each of the bolts 234 also carries a metal strip ll extending to the top of each aperture II, said strip constituting one terminal of an adjustable spark gap.

The bolts Ila either constitute contacts themselves, or are can by metal strips ii to contacts Ila, dis in a circle around a pivot 32 supported by the panel II. A radial contactor it carried by the said pivot is adapted to establish contact successively with the bolts 23a or contacts ila. l'rom the pivot 32, a metal strip 34 provides an electrical connection to the metal clip I. which engages one electrode of the luminous discharge tube l'l. Thus, when the leads 24 are connected to the spark plugs of an auto-- mobile engine: the contactor It is adapted upon rotation to connect one electrode of the discharge is in themetal tube II successively 'with each of the high ten- I sion terminals of the said spark plugs.

The metal clip ll, engaging the other electrode of the discharge tube, is joined to the metal casing ll of the testing device, which is. grounded as hereinafter described, so that the discharge tube reacts to the excitation provided by the intermittent high tension voltage supplied to the spark plug terminal to whichit is joined by a luminous flash which may be observed by an operator through the window 2|.

The pivot 32 comprises a rod .35. extending through the panel 12 and facing l4, and carrying on its outer end a knob 38 of insulating material secured thereto by means of a set screw 31 which engages a flattened portion of the said rod. At its inner end, the rod. 35 is rigidly secured to the contactor it which overlies and engages one end of the strip 34. A spring washer I! urges the strip 84 against the contact 33 thus forming a secure electric connection between the two. A pair of ears is bent outwardly from the edges of the strip 34 may be provided to limit the arcuate motion of the contactor 33. The knob 30 carries a pointer "a which indicates, by means of suitable indicia on the facing of the panel, the position of the contactor l3 behind the panel. Thus, bymanipulation of the knob 35, the contactor 83 may be adjusted to establish a circuit from. the desired spark plug to the discharge tube ll.

As hereinbefore stated,,the fixed contact of the adjustable spark gap behind each of the apertures 2| consists of the metal strip 30. According to the present invention, an adjustable con- .tact of novel construction is provided for cooperation therewith. The latter comprises a metal carrier strip, fixed to the panel and having a stud engaging a longitudinal slot in a movable strip which constitutes the adjustable contact of the spark gap. Resilient means is preferably provided for urging the slotted strip against the fixed supporting strip to hold the former frictionally in any position of adjustment, but permitting relative sliding motion of the said strips upon application of a suitable force. By sliding the slotted strip over the stud, one end thereof may be moved toward or away from the fixed contact of the spark gap. Means for actuating and guiding the adjustable contact comprises a radial arm engaging the other end of the slotted strip, and rigidly secured to a pivot journaled in the panels, which may be rotated-by means of a control knob on the opposite side of the panel. By rotation of the knob, the spacing between the end of the slidable strip constituting the movable spark gap terminal, and the fixed spark gap terminal may be adjusted as desired. Preferably, a pointer or mark on the knob, and a scale on the facing of the panel are provided to indicate the adjustment of the spark gap.

As shown in the accompanying drawings, the supporting metal strip comprises a metal strip ll secured by bolts a to the rear surface 'of the panel below the apertures 2| and connected by means of an insulated'lead ll passing through an insulating bushing 25a in the wall of the casing II to a spring clip 2 similar in construction, but larger than the clip 26', At one end, the strip 40 is connected electrically to the metal wall of the casing II. The clip 42 is adapted to be secured'to the portion of the engine block, such as a bolt 3, constituting a ground connection. Accordingly, the casing ll of the testgrounded through the said strip and 1 the stud like a rivet to the strip 40.

A metal contact strip 46 engages the protruding portion of the stud 44 by means of a longitudinal slot 47, and is retained thereon by the enlarged head 44a of the stud. A pair of convex spring washers 48 which are carried by the stud and inserted between the head 44a of the stud and the contact strip 46 with their concave surfaces facing each other, normally urge the strip 46 against the strip 40. By this means, a secure electrical connection between the strip 40 and the strip 46 is secured and the latter is frictionally held against casual movement with reference to the former.

One end of each of the strips 46 is cut to a point as indicated at 49, the pointed end forming an electrode for the spark gaps behind the apertures 2| in the panel.

The slot 41 is so disposed that when the strip 46 is slid over the stud 44 to one limit of its motion, the pointed end 49 is adapted to form a direct contact with the fixed terminal strip 30 extending to the top of the aperture 2| whereby the spark gap behind the aperture is short-circuited. Motion of the strip 46 toward the other limit of its motion is adapted to widen the spark gap between the point 49 and the strip 36.

In order to control the position of the strip 46, each is provided with an aperture 56 near the end opposite the point 49, said aperture being engaged by a hook on the end of a radial arm 52 carried by a pivot 53. The latter comprises a rod 54 extending through the panel i2 of the facing i4. The arm 52 is rigidly secured to the inner end of the rod, while a knob 55 having a, pointer 55a is secured to the outer end of the said rod, which protrudes through the panel facing, in the same manner as the knob 36 carried by the rod 35.

Engagement of the hook 5! on the radial arm 52 with the aperture 50 in the control strip 46 retains the pointed end 49 of the latter behind the aperture 2 i in the position shown in Fig. 2.

The angular disposition of the arm 52 is such that rotation of the knob 55 through a limited arc moves the pointed end of the strip 46 across the apertures 2| toward or away from the fixed contact 30. Such angular disposition of the arm 52 and the strip 46 is shown in Fig. 2.

The facing l4 of the panel bears suitable indicia as shown in Fig. 1, indicating, for instance, in millimeters, the approximate gap between the end 49 of the strip 46 and the corresponding contact 3D for any position of the pointer 55a of the said knob. At one end of the range of the pointer, shown at the left of each of the knobs in Fig. 1, the spark gap behind the corresponding apertures 2| is short-circuited so that when leads 24 and 4| are attached respectively to the spark plug and ground connection of an automobile engine, and the pointer is moved all the way to the left, the spark plug of the engine will be short-circuited and will cease to function.

At one side of the testing device, a cup or reservoir 56 is mounted on a bracket 51 secured to the side wall of the metal casing Ii by means of threaded bushing 66 extending through a central aperture in the base of the cup 66 and a corresponding aperture in the bracket 61, the bushing being clamped into position by means of a lock nut 69. A hollow cylindrical cap 60 is provided having anvinternally threaded portion 6|, adapted to engage the threads of the bushing 66, extending a short distance inward from the mouth of the cap and terminating in an inwardly extending annular shoulder "62 for engaging the end of the said bushing.

Inwardly of the said shoulder, the cap 60 is hollow to provide a chamber 63 housing a filter screen 64 in the shape of a cylindrical cup. The filter screen is provided with an annular flange 64a adapted to engage the annular shoulder 62. In assembling the cap 66 with the bushing 68, the screen 64 is inserted into the chamber 63 with the flange 64a resting on the shoulder 62 and threaded portion of the cap is screwed on to the end of the bushing 66 protruding from the base of the lock nut 69 until the end of the bushing clamps the flange 64a against the shoulder 62. At the lower end of the cap 66, a protruding nozzle 66 is provided having an annular flange 66a at its outer end.

The said reservoir is adapted to supply a treatment liquid by gravity feed to the cylinders of an automobile motor by way of the Venturi intake of the carbureter. It is necessary that the rate of feed be regulated to avoid unequal distribution of the liquid in the cylinders supplied by the venturi. According to the present invention, in order to supply the fluid at a uniform rate, an outlet comprising the nozzle at the lower end of the reservoir is provided with a constriction of such size as to regulate the flow of the liquid to a suitable rate. By this means, no adjustment is necessary to obtain the desired rate of the flow.

In the accompanying drawings, the said means which automatically regulates the flow of the liquid consists of a constricted passage 66 formed at the lower end of the chamber 63 of the cap 66, and providing a communicating passage between said chamber and the bore of the nozzle 66.

A length of flexible tubing 61 of oil-resistant material, such as neoprene, is slipped over the nozzle member 65 and clamped thereto by means of a split annular clamp 61a, retention of the tubing being aided by the flange 65a on the end of the nozzle. At the opposite end of the tube 6l, a short length of metal tubing 66 is preferably inserted therein and clamped thereto by means of a split annular clamp 61b. The protruding end of the metal tubing 68 constitutes a substantially rigid outlet for the flexible tube 61'.

In order to facilitate introduction of a treatment liquid into the cylinders of an automobile engine by way of the Venturi tubes of the carbureter, means for supporting the outlet tube in the Venturi of the carbureter is provided, comprising a spring clip 16 as shown in Fig. 6 having a hook H at one end for engaging the edge of the carbureter intake, an outwardly bent elbow 12 intermediate its ends, and an outwardly bent ear 13 at the opposite end thereof, said ear and elbow being apertured to engage and frictionally retain the outlet tube 66 when the latter is inserted therethrough. The location of the apertures in the elbow and the ear is constructed so that the outlet tube 68 is supported in a position extending into a venturi of the carbureter when the hooked end II of the said clip is supported in engagement with the edge of the carbureter air intake.

According to the present invention, the testing device, including the reservoir, is mounted on a support in such a manner that it may be conveniently adjusted in such a position above the motor as to permit easy manipulation and ob servation of the device. This means for supporting the testing device comprises a rigid support rod having a ball mounting on the end thereof, cooperating with a socket formed in the casing I I of the testing device, and a clamp for securing the ballmounting in th said socket. By this means, the testing device may be universally adjusted in any desired position above the motor of an automobile engine to be tested.

Means for supporting the testing device of the present invention is shown in Fig. 3, and preferably compirses a spherical ball mounting 15 carried on the end of a rigid supporting rod 16, said ball mounting engaging the aperture in the rear wall of the casing I I. Preferably, a thickened reenforcing plate '11, having a depression I8 forming a socket for the ball mounting, is positioned against the inner surface of the casing I I in such a manner that the socket 18 is aligned with the aperture in the said wall.

An L-shaped clamp member 19 having a forked end 80 for engaging the opposite side of the ball mounting i5 is provided, the other end of the said clamp being supported against the outer surface of the casing ll opposite a portion of the reenforcing plate ll. A bolt 8i passing through an aperture intermediate the ends of the clamping member and through an aligned aperture in the wall of the casing It is threaded into the reenforcing plate ll. By assembling the parts of the clamp and tightening the bolt 8 i, the plate H and clamp 19 are drawn together clamping the ball mounting between the socket 18 and the forked end Bil of the clamping member, while the wall of the casing I I is clamped between the plate l1 and the supported end of the clamping member. Upon loosening the bolts BI slightly, the device may be adjusted in any desired position with reference to the support arm 16, and retained in the adjusted position by tightening the bolt. If desired, plate 11 may be spot welded to the wall of the casing II or otherwise secured thereto. The clamping member 19 is preferably provided with webs 82 at its sides to reenforce the elbow formed by the two ends thereof.

The device is used according to the present invention in the following manner. The arm is adjusted so that it supports the device above the automobile motor to be tested. The ball and socket mounting is adjusted so that the panel of the device is conveniently accessible for manipulation and observation. The clips 26 are attached to the spark plug terminals as shown in Fig. 5 and the knobs are turned all the way to the right so that the spark gaps controlled thereby will be ineffective to shunt out the corresponding spark plugs. The motor is started and adjusted to run at a medium speed corresponding, for instance, to about twenty-five miles per hour in high gear.

The contactor 33 is then moved successively to each of the positions for connecting the discharge tube I! successively to each of the spark plug terminals by rotating the knob 36. If the illumination of the tube for each plug is regular, uniform, and bright, it indicates that the ignition is satsfactory. Relatively dim or irregular illumination, or absence of illumination, indicates that the ignition is faulty. The trouble may then be sought in the spark plug itself, or in the wiring and the distributor circuits associated therewith.

By virtue of the disposition of the discharge tube behind a window in the panel of the closed casing, observation and comparison of the intensity of the illumination is facilitated, the tube being seen against the dark background and the angle of observation remaining substantially constant. Furthermore, by using a single tube, the various spark plugs may be compared with each other, whereas the use of a separate tube for each spark plug would introduce as a variable the differences in the characteristics of the tubes themselves, which would interfer with such a comparison.

An indication of the source of the trouble is provided by manipulation of the spark gap between the movable contact strips 46 and the fixed strip 30 connected to the spark 'plug being tested. This is accomplished by moving the knob 55 slowly from right to left, thereby decreasing the gap between the movable part 49 and the strip 30 until an intermittent spark appears in the circular window 2 I. When this effect is first observed, the approximate resistance of the spark plug points may be read from the position of the pointer 55a on the millimeter scale on the panel facing. If it exceeds approximately one millimeter, the spacing of the point is too wide or the resistance of the plug is too high due to corrosion, and the faulty operation may generally be corrected by cleaning and resetting the spark plug points.

If the indicated spark gap is within the correct range, that is from about 0.5 to 1 millimeter, the trouble may be sought in the wiring or distributor circuit associated with the said spark plug. To test this, the lead from the spark plug terminal to the distributor is disconnected and the clip 28 attached to the said lead. While the engine is running, the knob 55 is again turned from right to left until a spark appears behind the aperture 2 I. The condition of the ignition wiring and distribu tor circuit is indicated by the position of the pointer 55a on the upper scale on the panel facing I4, which indicates whether the operation of the spark is normal, fair or weak. If the latter ranges are indicated, faulty insulation of the wiring or a fault in the distributor is probably the cause of the trouble, and the necessary repairs may then be undertaken.

As hereinbefore set forth, the disposition of the adjustable spark gaps behind the windows in the panel facilitates observation of the spark, since it is seen against a dark background. Furthermore, by providing lens-shaped sight windows, the effect is magnified and also aids in such observation. Moreover, by enclosing the spark gap in a closed casing, the spark is protected from access of explosive gases and fumes which are often present in garages and which may arise from the carbureter or the gas pump of the motor being tested. Thus, the danger of explosion or fire is substantially eliminated by the aforesaid arrangement.

A further advantage of the device is the fact that all of the high tension contacts are on the inside of the casing and the operator is protected from shock thereby.

Since spark plugs which operate normally under no load conditions sometimes break down when subjected to increased compression resulting under full load conditions, it is advantageous in testing the spark plugs according to the presaaaasos ent invention to carry out the test under load. For this purpose, all oi. the cylinders except one or two to be tested are rendered inoperative by short circuiting their spark plug terminals, or by disconnecting the leads i'rom the distributor to their spark plugs. The cylinders under test then operate against the compression oi the other cylinders, which is equivalent to p ration under full load conditions.

It the number of cylinders is the same as or less than that oi the number oi leads 24 oi the testing device, the adjustable spark gaps associated therewith may be used to cut out the cylinders which are not being tested, merely by turning each oi the knobs ll corresponding to said cylinders all of the way to the leit, thus bringing the movable strips 48 into contact with the ilxed strips 30, and short circuiting the spark plugs connected thereto. The device has been shown as having four high tension leads and ad- Justable spark gaps, but obviously any number may be provided, or if desired, more than one of the testing devices as shown may be simultaneously used for this purpose.

The cylinders operating under load are then tested in the manner hereinbeiore described by means of the luminous discharge tube and if the operation is found to be faulty, the spark plug may be replaced or cleaned as the case may require.

The reservoir 56 is provided for introducing a treatment liquid into the cylinders, the liquid acting as a penetrating solvent for gum deposited in the cylinders, and around the valves. The solvents generally used are in general petroleum products which are combustible. Accordingly, it is necessary to introduce the liquid into the cylinders while the latter are not firing so that it may exert its solvent action without combustion. Otherwise, it would be almost immediately burned and its beneficial eil'ect lost.

The liquid is introduced into the motor from the reservoir through a venturi oi the carbureter, by inserting the outlet tube 62 therein as indicated in Fig. 6. In the case of a dual carbureter having two venturis, each supplying halt of the cylinders, the leads 24 of the testing device are connected to the spark plug oi the cylinders to be treated. By moving all of the knobs ii to the left, the spark plugs of the said cylinders are short-circuited while the motor runs on the cylinders supplied by the other venturi oi the carburetor.

A suitable amount of treating liquid is then placed in the reservoir, and according to the present invention it runs into the venturi at a rate determined by the size of the constriction 58, no adjustment being necessary to regulate the flow. The amount 0! liquid which is used is determined by the number of cylinders in be treated, for instance. two ounces of liquid ar in general suiiicient tor each cylinder.

Ii there is only one venturi in the carburetor, one half of the cylinders are treated at a time by short-circuiting hall or the spark plugs in the above described manner, the liquid entering the other cylinders being allowed to beburned up. Obviously, this requires twice the amount of treatment liquid for degumming the entire engine.

Preferably, the testing of the spark plugs is repeated alter the treatment with fluid, since particles of carbon loosened by the treatmentmay become lodged between the spark plug pointer and interiere with proper ignition.

Variations and modifications may be made withinthescopeoithisinventionandportims oi the improvements may be used without others. a

I claim:

1. In an ignition testing device ior internal combustionengineaaclosedhousinghavinga sightopeningthereln; asingle luminous electric discharge tube mounted behind laid lllht opening; means ior one terminal or the said discharge tube directly to a ground: a plurality of contacts insulatedly carried within the housing; insulated means for said contacts to the high tension terminals of the spark plugs in an internal combustion engine; means within the casing ior selectively connectin! said contacts to the other terminal of said discharge tube: insulated means on the exterior oi the casing for manually adjusting the position of said connecting means; a plurality of switches within the casing for connecting one or more 01' the contacts to the ground; and manual control means on the exterior or the casing for adjusting said switches individually in contactgrounding position.

2. In an ignition testing device for internal combustion engines, a closed casing having a plurality oi sight openings therein: translucent means for covering said sight openings: a pair oi terminals within the casing disposed respectively at opposite sides 01 each or said openings. constituting a spark gap; means for connecting one terminal 01' each pair to a ground: insulated means for connecting each opposite terminal respectively to a portion of the high tension ignition circuit oi an internal combustion engine: manually operable means having an insulated portion carried on the exterior of the casing for manual ustment thereof, said manual means moving contacts behind the said sight 0pmings toward or away from each other, the range or movement of each 01' said pairs of terminals including at least one position in which they are mutually engaged; and means for retaining said contacts against casual movement in any adiusted position.

8. In an ignition testing device for internal combustion engines, a closed casing having a plurality of sight openings. therein; t means for covering said sight a pair oi terminals within the casing mtively at opposite sides of each oi said openings. constituting a spark gap; means ior connecting one terminal oi each pair to a ground; means for connecting each opposite terminal respectively to a portion of the high tension ignition circuit of an internal c engine; manually operable means having an insulated portion carried on the exterior of the casing for manual adiustment thereof, said manual means moving the contacts behind the said sight openings toward or away from each other, the range or movement or each pair oi e -m c including at least one position in which they are mutually engaged: means for retaining said contacts against casual movement in any adjusted position; and means on the exterior or the casin! for indicating the distance between the terminals or each spark gap.

4. In an ignition testing device tor internal combustion engines, a closed casing having a plurality of S ght openings therein; transiucent windows covering each of said light a single luminous electric discharge tube behind one of said sight openings; a ground for one or the terminals of said discharge tube: a plurality of contacts insulatedly carried-within the casing; insulated means for connecting said contacts respectively to the high tension terminals of the spark plugs of an internal combustion engine; adjustable means within the casing for selectively connecting said contacts to the opposite terminal of said discharge tube; a plurality of fixed spark gap terminals, each insulatedly mounted within the casing at one side of each of the remaining sight openings, said terminals being connected respectively to said contacts; a movable spark gap terminal extendin to the opposite side of each of the latter sight openings; means connecting the latter terminals to the ground; means for independently moving each of the movable spark gap terminals across the sight openings toward or away from the fixed terminals at the opposite sides of said openings, said movable terminals contacting the fixed terminals at the limit of their movement toward the latter; and manual control means on the outside of the casing for adjusting the position of said movable spark gap terminals individually, and of said discharge tube connecting means.

5. In an ignition testing device having a casing, a plurality of leads for connecting portions of said device with portions ofthe ignition system of an automobile engine, and control and indicating means on the exterior of said casing, means for supporting said casing above said engine, comprising a rigid support rod adapted to extend over said engine, the end of said rod engaging said casing by means of a universally adjustable ball and socket joint; and means for clamping said joint in any desired position of adjustment.

6. In an ignition testing device having a casing, a plurality of leads for connecting portions of said device to portions of the ignition system of an automobile engine, and control and indicating means on the exterior of said casing, means for supporting said casing above said engine, comprising a rigid support member adapted to extend over the engine; a ball mounting carried at an extremity of said member, said ball mounting engaging a socket formed in the casing of said testing device; an L-shaped clamp member having a forked end engaging said ball mounting on the side opposite that engaged by said socket, and the other end supported against the wall of the casing at a point spaced apart from said socket; and draft means extending intermediate said socket and the end of the clamp supported against the said wall, for drawing the clamp and casing together, and thereby clamping the ball mounting between the forked end of the clamp and the socket in the wall of the casing.

7. In an ignition testing device, an adjustable spark gap comprising a support, a spark gap terminal secured in fixed position to said support; a movable spark gap terminal mounted for linear sliding movement on said supporting means toward or away from said fixed terminal; means for retaining said slidable terminal in any desired position of adjustment; and means for connting said terminals respectively to a ground and to a portion or the high tension circuit of the ignition system of an automobile engine.

8. In an ignition testing device, an adjustable spark gap comprising a support; a spark gap terminal secured in fixed position to said support; a movable spark gap terminal mounted for linear sliding movement on said support; a rotatable member carried by the support having an eccentric portion engaging said slidable terminal so as to provide a two-way driving connection therewith for moving it positively toward or away from said fixed terminal; means for retaining said slidable terminal in any desired position of adjustment; and means for connecting said terminals respectively to a ground and to a portion of the high tension circuits of the ignition system of an automobile.

9. In an ignition testing device, an adjustable spark gap comprising a support, a spark gap terminal secured in fixed position to said support; a movable spark gap terminal mounted for linear sliding movement on said supporting means toward or away from said fixed terminal; resilient frictional means carried by said support and engaging said slidable terminal for retaining said slidable terminal in any desired position of adjustment; and means for connecting said terminals respectively to a ground and to a portion of a high tension circuit of the ignition system of an automobile engine.

10. In an ignition testing device, an adjustable spark gap comprising a support; a spark gap terminal secured in fixed position to said support; a movable spark gap terminal mounted for linear sliding movement on said support; a rotatable member carried by the support having an eccentric portion engaging said slidable terminal so as to provide a two-way driving connection therewith for moving it positively toward or away from said fixed terminal, said movable terminal forming a contact with said fixed terminal at one limit of its motion; means for retaining said slidable terminal in any desired position of adjustment; and means for connecting said terminals respectively to a ground and to a portion of the high tension circuits 01' the ignition system of an automobile.

11. In an ignition testing device, an adjustable I spark gap comprising a support; a spark gap terminal secured in fixed position to said support; a movable spark gap terminal mounted for linear sliding movement on said support; a rotatable member carried by the support having an eccentric portion engaging said slidable terminal so as to provide a two-way driving connection therewith, for moving it positively toward or away from said fixed terminal; an indicator carried by said rotary member and cooperating with suitable indicia on the support for indicating the spacing between said spark gap terminals; resilient friction means for retaining said slidable terminal in any desired position of adjustment; and means for connecting said terminals respectively to a ground and to a portion of the high tension circuits of the ignition system 0! an automobile.

, 12. In an ignition testing device for automobile engines, a panel; a sight opening in said panel; a spark gap terminal secured in fixed position to said panel and extending to one side of said sight opening; a movable spark gap terminal mounted for linear sliding movement on said panel; a rotatable member extending through said panel and journaled therein, having an eccentric portion engaging said slldable terminal so as to provide a two-way driving. connection therewith for moving it positively toward or away from said fixed terminal across the sight opening in the panel; insulated means carried by said rotatable member on the side oi. the panel opposite said terminals for manually adjusting said member; resilient frictional means for retaining said slidable terminal in any desired position of adjustment; and means for connecting said terminals respectively to a ground and to a portion of the high tension circuits of the ignition system of an automobile.

13. In an ignition testing device for automobile engines, a panel of insulating material; a plurality of sight openings in said panel; a plurality of fixed spark gap terminals secured to said panel to extend respectively to the sides of said sight openings; insulated means for connecting said terminals respectively to portions of a high tension circuit of the ignition system of an automobile; a metal carrier strip secured to said panel; means for connecting said carrier strip to a ground; a plurality of movable spark gap terminals mounted for linear sliding movement upon and engaging said carrier strip; a plurality of rotatable members extending through said panel and journaled therein, having eccentric portions respectively engaging portions of said slidable spark gap terminals so as to provide a two-way driving connection therewith for moving the'same toward or away from the corresponding fixed terminals across the sight openings in the panel; means carried by each of said rotary members on the side of the panel opposite said spark gap terminals for manually adjusting said slidable terminals; and resilient fric- I tional means for retaining the slidable terminals in any desired position of adjustment.

14. An ignition testing device as defined in claim 1, wherein each of said plurality of switches comprises a pair of relatively movable terminals,

one connected to one of said high tension con-- tacts, and the other having a ground connection, the terminals of each switch being movable by said manual control means to engage each other for grounding the corresponding high tension contact and being adjustably separable thereby to increase'the spacing thereof progressively so as to constitute a variable spark gap, said housing having a sight window therein adjacent the switch terminals for observing the operation or said spark gap.

15. In an ignition testing device for internal combustion engines, a closed housing having a sight opening therein; a single luminous electric discharge tube mounted behind said sight opening; a plurality of contacts insulatedly carried within the housing; insulated means for connecting said contacts to the high tension terminals of the spark plugs in an internal combustion engine; means within the casing for selectively connecting said contacts to a'terminal of said discharge tube; insulated means on the exterior of the casing for manually adjusting the position of said connecting means; a plurality of switches within the casing for connecting one or more of the contacts to the groundrand manual control means on the exterior of the casing for adjusting the said switches individually in contact grounding position.

16. In an ignition testing device for internal combustion engines, a closed casing having a plurality of sight openings therein; translucent windows' covering each of said sight openings; a single luminous electric discharge tube behind one of said sight openings; a plurality of contacts insulatedly carried within the casing; insulated means for connecting said contacts respectively to the high tension terminals of the spark plugs in an internal combustion engine; adjustable means within the casing for selectively connecting said contacts to a terminal of said luminous discharge tube; a plurality of independently adjustable spark gaps, each comprising a pair of relatively movable terminals within the casing behind the remaining sight openings, said pairs of terminals being adjustable to contact each other in one adjusted position; means for connecting one terminal of each spark gap to a ground; means connecting the opposite terminals of said spark gaps respectively to said high tension contacts; and manual control means on the outside of the casing for adjusting said spark gaps individually, and for adjusting said discharge tube connecting means.

HERBERT G. LEHMANN. 

